Fix query params not being used in Intercom::BaseCollectionProxy

Arbitrary @query params could be passed in to filter resources, e.g. via
the `#find_all` method. These params were not being forwarded through to
the underlying HTTP client by BaseCollectionProxy in the same way that
they are in ClientCollectionProxy.

Author: tdooner

lib/intercom/base_collection_proxy.rb

@@ -68,10 +68,7 @@ def has_next_link?(response_hash)
     end
 
     def payload
-      payload = {}
-      payload[:per_page] = @params[:per_page] if @params[:per_page]
-      payload[:starting_after] = @params[:starting_after] if @params[:starting_after]
-      payload
+      @params.keep_if { |k, v| !v.nil? }.to_h
     end
   end
 end

spec/unit/intercom/base_collection_proxy_spec.rb

@@ -44,4 +44,9 @@
     contacts.each { |contact| emails_iter2 << contact.email }
     _(emails_iter1).must_equal emails_iter2
   end
+
+  it "supports query params" do
+    client.expects(:get).with("/conversations", {:intercom_user_id => 'abcdef0000'}).returns(test_conversation_list)
+    _(client.conversations.find_all(:intercom_user_id => 'abcdef0000').map(&:id)).must_equal %w[147]
+  end
 end